/// Highest quality but slowest execution time.
wxIMAGE_QUALITY_BICUBIC,
- /// Default image resizing algorithm used by wxImage::Scale().
+ /**
+ Use surrounding pixels to calculate an average that will be used for
+ new pixels. This method is typically used when reducing the size of
+ an image.
+ */
+ wxIMAGE_QUALITY_BOX_AVERAGE,
+
+ /**
+ Default image resizing algorithm used by wxImage::Scale(). Currently
+ the same as wxIMAGE_QUALITY_NEAREST.
+ */
wxIMAGE_QUALITY_NORMAL,
- /// Best image resizing algorithm, currently same as wxIMAGE_QUALITY_BICUBIC.
+ /**
+ Best image resizing algorithm. Since version 2.9.2 this results in
+ wxIMAGE_QUALITY_BOX_AVERAGE being used when reducing the size of the
+ image (meaning that both the new width and height will be smaller than
+ the original size). Otherwise wxIMAGE_QUALITY_BICUBIC is used.
+ */
wxIMAGE_QUALITY_HIGH
};
{
wxPNG_TYPE_COLOUR = 0, ///< Colour PNG image.
wxPNG_TYPE_GREY = 2, ///< Greyscale PNG image converted from RGB.
- wxPNG_TYPE_GREY_RED = 3 ///< Greyscale PNG image using red as grey.
+ wxPNG_TYPE_GREY_RED = 3, ///< Greyscale PNG image using red as grey.
+ wxPNG_TYPE_PALETTE = 4 ///< Palette encoding.
};
/**
the wxBitmap::wxBitmap(wxImage,int depth) constructor.
This bitmap can then be drawn in a device context, using wxDC::DrawBitmap.
+ More on the difference between wxImage and wxBitmap: wxImage is just a
+ buffer of RGB bytes with an optional buffer for the alpha bytes. It is all
+ generic, platform independent and image file format independent code. It
+ includes generic code for scaling, resizing, clipping, and other manipulations
+ of the image data. OTOH, wxBitmap is intended to be a wrapper of whatever is
+ the native image format that is quickest/easiest to draw to a DC or to be the
+ target of the drawing operations performed on a wxMemoryDC. By splitting the
+ responsibilities between wxImage/wxBitmap like this then it's easier to use
+ generic code shared by all platforms and image types for generic operations and
+ platform specific code where performance or compatibility is needed.
+
One colour value of the image may be used as a mask colour which will lead to
the automatic creation of a wxMask object associated to the bitmap object.
- wxBMPHandler: For loading (including alpha support) and saving, always installed.
- wxPNGHandler: For loading and saving. Includes alpha support.
- wxJPEGHandler: For loading and saving.
- - wxGIFHandler: Only for loading, due to legal issues.
+ - wxGIFHandler: For loading and saving (see below).
- wxPCXHandler: For loading and saving (see below).
- wxPNMHandler: For loading and saving (see below).
- wxTIFFHandler: For loading (including alpha support) and saving.
Loading PNMs only works for ASCII or raw RGB images.
When saving in PNM format, wxPNMHandler will always save as raw RGB.
+ Saving GIFs requires images of maximum 8 bpp (see wxQuantize), and the alpha channel converted to a mask (see wxImage::ConvertAlphaToMask).
+ Saving an animated GIF requires images of the same size (see wxGIFHandler::SaveAnimation)
@library{wxcore}
@category{gdi}
@li wxBITMAP_TYPE_PNG: Load a PNG bitmap file.
@li wxBITMAP_TYPE_PCX: Load a PCX bitmap file.
@li wxBITMAP_TYPE_PNM: Load a PNM bitmap file.
- @li wxBITMAP_TYPE_TIF: Load a TIFF bitmap file.
+ @li wxBITMAP_TYPE_TIFF: Load a TIFF bitmap file.
@li wxBITMAP_TYPE_TGA: Load a TGA bitmap file.
@li wxBITMAP_TYPE_XPM: Load a XPM bitmap file.
@li wxBITMAP_TYPE_ICO: Load a Windows icon file (ICO).
/**
Gets a user-defined string-valued option.
- Currently the only defined string option is
+ Generic options:
@li @c wxIMAGE_OPTION_FILENAME: The name of the file from which the image
was loaded.
+ Options specific to wxGIFHandler:
+ @li @c wxIMAGE_OPTION_GIF_COMMENT: The comment text that is read from
+ or written to the GIF file. In an animated GIF each frame can have
+ its own comment. If there is only a comment in the first frame of
+ a GIF it will not be repeated in other frames.
+
@param name
The name of the option, case-insensitive.
@return
The function is case-insensitive to @a name.
If the given option is not present, the function returns 0.
- Use HasOption() is 0 is a possibly valid value for the option.
+ Use HasOption() if 0 is a possibly valid value for the option.
Generic options:
@li @c wxIMAGE_OPTION_MAX_WIDTH and @c wxIMAGE_OPTION_MAX_HEIGHT: If either
the resulting PNG file. Use this option if your application produces
images with small size variation.
+ Options specific to wxTIFFHandler:
+ @li @c wxIMAGE_OPTION_TIFF_BITSPERSAMPLE: Number of bits per
+ sample (channel). Currently values of 1 and 8 are supported. A
+ value of 1 results in a black and white image. A value of 8 (the
+ default) can mean greyscale or RGB, depending on the value of
+ @c wxIMAGE_OPTION_TIFF_SAMPLESPERPIXEL.
+ @li @c wxIMAGE_OPTION_TIFF_SAMPLESPERPIXEL: Number of samples
+ (channels) per pixel. Currently values of 1 and 3 are supported.
+ A value of 1 results in either a greyscale (by default) or black and
+ white image, depending on the value of
+ @c wxIMAGE_OPTION_TIFF_BITSPERSAMPLE. A value of 3 (the default)
+ will result in an RGB image.
+ @li @c wxIMAGE_OPTION_TIFF_COMPRESSION: Compression type. By default
+ it is set to 1 (COMPRESSION_NONE). Typical other values are
+ 5 (COMPRESSION_LZW) and 7 (COMPRESSION_JPEG). See tiff.h for more
+ options.
+ @li @c wxIMAGE_OPTION_TIFF_PHOTOMETRIC: Specifies the photometric
+ interpretation. By default it is set to 2 (PHOTOMETRIC_RGB) for RGB
+ images and 0 (PHOTOMETRIC_MINISWHITE) for greyscale or black and
+ white images. It can also be set to 1 (PHOTOMETRIC_MINISBLACK) to
+ treat the lowest value as black and highest as white.
+ If you want a greyscale image it is also sufficient to only specify
+ @c wxIMAGE_OPTION_TIFF_PHOTOMETRIC and set it to either
+ PHOTOMETRIC_MINISWHITE or PHOTOMETRIC_MINISBLACK. The other values
+ are taken care of.
+
+ @note
+ Be careful when combining the options @c wxIMAGE_OPTION_TIFF_SAMPLESPERPIXEL,
+ @c wxIMAGE_OPTION_TIFF_BITSPERSAMPLE, and @c wxIMAGE_OPTION_TIFF_PHOTOMETRIC.
+ While some measures are taken to prevent illegal combinations and/or
+ values, it is still easy to abuse them and come up with invalid
+ results in the form of either corrupted images or crashes.
+
@param name
The name of the option, case-insensitive.
@return
@li wxBITMAP_TYPE_PNG: Load a PNG bitmap file.
@li wxBITMAP_TYPE_PCX: Load a PCX bitmap file.
@li wxBITMAP_TYPE_PNM: Load a PNM bitmap file.
- @li wxBITMAP_TYPE_TIF: Load a TIFF bitmap file.
+ @li wxBITMAP_TYPE_TIFF: Load a TIFF bitmap file.
@li wxBITMAP_TYPE_TGA: Load a TGA bitmap file.
@li wxBITMAP_TYPE_XPM: Load a XPM bitmap file.
@li wxBITMAP_TYPE_ICO: Load a Windows icon file (ICO).
@li wxBITMAP_TYPE_PNG: Load a PNG bitmap file.
@li wxBITMAP_TYPE_PCX: Load a PCX bitmap file.
@li wxBITMAP_TYPE_PNM: Load a PNM bitmap file.
- @li wxBITMAP_TYPE_TIF: Load a TIFF bitmap file.
+ @li wxBITMAP_TYPE_TIFF: Load a TIFF bitmap file.
@li wxBITMAP_TYPE_TGA: Load a TGA bitmap file.
@li wxBITMAP_TYPE_XPM: Load a XPM bitmap file.
@li wxBITMAP_TYPE_ICO: Load a Windows icon file (ICO).
/**
Initializes all available image handlers.
- This function call wxImage::AddHandler() for all the available image
+ This function calls wxImage::AddHandler() for all the available image
handlers (see @ref image_handlers for the full list). Calling it is the
simplest way to initialize wxImage but it creates and registers even the
handlers your program may not use. If you want to avoid the overhead of
projects / wxWidgets.git / blobdiff